The duel in the pool turned out to be a one-man show: Ryan Lochte won the 400
metres individual medley with an imposing swim, leaving the field, including
Michael Phelps, in his imperious wake.

It was a humbling experience for Phelps who could only finish fourth. This was the first time the greatest swimmer in history had finished off the podium in an Olympic final, since coming fifth at the Sydney 2000 Games.

For Lochte, this was the day he came out of Phelps’s Olympic shadow. Phelps had stopped racing the 400m medley after Beijing but had come back to try to replicate the glory of four years ago. Lochte, the world champion, showed him there is a new king in the pool in this most gruelling of events.

“For four years I’ve been training hard,” Lochte said. “This is just my first event so I’m really happy. I’m ready to rock this Olympics. I was in kind of shock at the end. I could hear the fans screaming and having my family here helped me a lot.”

Thiago Pereira, of Brazil, had the swim of his life coming in second while Kosuke Hagino, 17, announced himself as a star of the future as he took bronze. Phelps will be determined not to become a star of the past.

“I’m a bit frustrated, I’m not feeling that great,” Phelps said. “I just want to put this race behind me and move on. It’s not the start I would have liked but I’ve just got to move up.

“I was lucky to get into the final.”

Phelps had indeed been lucky to make the final, coming just a fraction of a second from elimination. Phelps and Lochte were supposed to go head to head in lanes four and five. Certainly their times in the US trials last month, in which Lochte had won but both had swum under 4min 8sec, suggested the rest were there to make up the numbers.

Then Phelps had a shocker in qualifying. He had been drawn against Laszlo Cseh, the European champion, and the two seemed to get caught up in racing each other.

&lt;noframe&gt;Twitter: Ryan Lochte - Great way to start off the 2012 Olympics. &lt;a href="http://search.twitter.com/search?q=USA" target="_blank"&gt;#USA&lt;/a&gt; on a mission. &lt;a href="http://search.twitter.com/search?q=Jeah" target="_blank"&gt;#Jeah&lt;/a&gt;&lt;/noframe&gt;

Phelps put on a late burst to touch in ahead of the Hungarian but the clock showed he had gone more than five seconds slower than in the trials.

There was a moment of panic after the end of the following heat before he realised he had squeezed in in eighth place. The greatest swimmer in history had come close to elimination in the heats: what separated him from humiliation was that 0.07sec touch ahead of Cseh.

So Phelps was reduced to the unexpected indignity of racing from lane eight, normally reserved for the rank outsider. Being on the outside lane is a big disadvantage – you have a blank wall on one side of you and it is hard to see what the quickest swimmers are doing in the central lanes.

Phelps refused to blame his lane position for his performance in the final but it could not have helped.

&lt;noframe&gt;Twitter: Michael Phelps - Not pleased with my race tonight at all... But tom is a new day! And a new race!!&lt;/noframe&gt;

He added: “The lane draw had nothing to do with me coming fourth, it was just a rubbish race. I was trying to find a gear I couldn’t find. I spent the last 100m struggling.”

Lochte took charge from the start, sending out a clear signal of his intention to dominate. Butterfly is supposed to be Phelps’s stroke. Yet Lochte was ahead of Phelps by the end of the first 100m.

Now it was Lochte’s speciality, the backstroke: the gap opened alarmingly fast. By the end of the backstroke he was inside world record pace.

As Lochte pulled away, Hagino started catching up with Phelps. By the end of the backstroke the Japanese was in second. With the breaststroke, Pereira forced his way into the mix, moving into second. By now Phelps was in fourth and struggling.

Still, he had the freestyle to come. Lochte was clear, even if he was now outside record pace, but surely Phelps could deliver a late burst?

The speed was just not there and Pereira and Hagino held on.

There is still plenty of Phelps to come – his hatred of defeat will bring tremendous motivation – but this was an ominous signal that the greatest talent the pool has seen is no longer the force he once was.